Selection and cloning methods

Abstract

Selection and cloning methods are disclosed that are effective for the selective multiplication of desired animals, for instance livestock animals. These methods can be used to expand populations of animals, and are particularly useful for duplicating animals selected based on traits that are measured after the animal is deceased. Certain embodiments include techniques useful for selecting a desirable bovine animal (e.g., a desirable steer) based at least in part on a measurable carcass trait. Also described are specific cloning techniques that involve repetitive (for instance, two) cycles of cloning, such as nuclear transfer cloning. In specific embodiments, a two-step cloning system is described, in which the nuclear donor of the first cloning cycle is an adult fibroblast cell and the nuclear donor of the second cloning cycle is a fetal fibroblast harvested from a fetus that arose from the first cloning cycle.

1 . A method for selecting and cloning a non-human animal, comprising: 
 identifying a group of non-human animals;    taking a cell sample from at least one animal from the identified group of non-human animals prior to or after slaughter;    preserving the cell sample;    obtaining post-mortem a measurement of at least one post-mortem characteristic of the at least one animal;    selecting from the at least one animal a subject animal to be cloned, based on the measurement of the at least one post-mortem characteristic; and    cloning the selected animal.    
   
   
       2 . The method of  claim 1 , wherein preserving the cell sample comprises one or more of: 
 culturing the cell sample to produce a cell culture; or    freezing at least a portion of the cell sample.    
   
   
       3 . The method of  claim 1 , wherein at least one ante-mortem and at least one post-mortem trait measurement are obtained.  
   
   
       4 . The method of  claim 1 , wherein the at least one post-mortem characteristic for which a measurement is obtained is a governmental quality grade or a marbling score.  
   
   
       5 . The method of  claim 3 , wherein at least one characteristic is an expected progeny difference (EPD).  
   
   
       6 . The method of  claim 3 , wherein at least one characteristic is individual average daily gain.  
   
   
       7 . The method of  claim 3 , wherein at least average daily gain and marbling score are measured.  
   
   
       8 . The method of  claim 1 , wherein the non-human animals are selected from among cattle, pigs, horses, goats, sheep, chickens, turkeys, mice, rats, monkeys, cats, dogs, reptiles, and captive wild animals.  
   
   
       9 . The method of  claim 1 , wherein the non-human animals are ruminants.  
   
   
       10 . The method of  claim 9 , wherein the ruminants are cattle.  
   
   
       11 . The method of  claim 1 , wherein the cell sample is taken from the at least one animal while the animal is alive.  
   
   
       12 . The method of  claim 1 , wherein the cell sample is taken from the at least one animal while the animal is dead.  
   
   
       13 . The method of  claim 1 , wherein the cell sample comprises a fibroblast.  
   
   
       14 . The method of  claim 1 , wherein the selected animal is: 
 a reproductively compromised male bovine (steer); or    a reproductively compromised female bovine.    
   
   
       15 . The method of  claim 1  where cloning comprises quiescent cell nuclear transfer, proliferating cell nuclear transfer, two-step nuclear transfer cloning, or gonadal cell cloning.  
   
   
       16 . The method of  claim 1  where cloning the animal comprises: 
 transferring nuclear material of the preserved cell to a first enucleated oocyte to generate a first couplet;    culturing the first couplet in vitro and/or in vivo for a sufficient length of time and under appropriate conditions to produce a first clone;    transferring nuclear material of a cell of the first clone to a second enucleated oocyte to generate a second couplet; and    generating a cloned animal from the second couplet.    
   
   
       17 . The method of  claim 16  where the first clone is a fetus when nuclear material is transferred to generate the second couplet.  
   
   
       18 . The method of  claim 16  where maturing the first couplet comprises maturing the couplet in vivo to a relative gestational age of at least 30 days.  
   
   
       19 . The method of  claim 1 , wherein the post-mortem characteristic is carcass weight, marbling, meat taste, ribeye area, percent retail product, meat shelf life, fat thickness, governmental quality standard, fatty acid saturation level, meat tenderness, meat yield, low fat or liver size.  
   
   
       20 . The method of  claim 1 , wherein cloning is performed after death of the selected animal.  
   
   
       21 . A cloned animal produced by the method of  claim 1 .  
   
   
       22 . A method of selecting and cloning a bovine animal, comprising: 
 identifying a group of bovine animals;    preserving a sample from each bovine animal, where the sample contains a fibroblast cell;    obtaining a measurement of at least one ante-mortem characteristic of the bovine animals;    slaughtering the group of bovine animals;    obtaining a measurement of at least one post-mortem characteristic of the bovine animals;    selecting at least one bovine animal to be cloned, based on at least one ante-mortem and at least one post-mortem measured characteristic; and    cloning the selected bovine animal from the preserved fibroblast cell, where cloning the fibroblast cell comprises: 
 transferring nuclear material of the preserved fibroblast cell to a first enucleated oocyte to generate a first couplet;  
 maturing the first couplet in vitro and/or in vivo for a sufficient length of time and under appropriate conditions to produce a fetus of at least 30 days gestational age;  
 aborting the fetus;  
 transferring nuclear material of a fibroblast cell of the fetus to a second enucleated oocyte to generate a second couplet; and  
 generating a cloned animal from the second couplet.  
   
   
   
       23 . A cloned bovine animal produced by the method of  claim 22.